There is a laser working machine of a background art having a work lifter of a rotary type at a working table and constituted to be easily able to carry in or carry out a work onto and from the working table by rotating the rotary work lifter by 180° as disclosed in JP-UM-B-6-233.
Meanwhile, when a workpiece or the like is pinched between a rotary work lifter and a working table or the like in the midst of rotating the rotary work lifter, the rotary work lifter cannot be rotated further and rotation thereof is interrupted, and when a drive source of the rotary work lifter continues generating a torque as it is, the rotary work lifter or the working table is finally destructed. Therefore, when rotation of the rotary work lifter is interrupted, the rotation needs to stop.
However, the rotary work lifter of the background art is not provided with means for detecting a situation of rotating the rotary work lifter at any time and therefore, even when rotation of the rotary work lifter is interrupted by pinching a work piece or the like, the interruption cannot be detected. Therefore, there poses a problem that since a position of finishing the rotation is not reached, the drive source continues generating the torque, and the rotary work lifter, the working table or the like is finally destructed.
The invention has been carried out in order to resolve the problem to provide a rotary work lifter having a protecting apparatus for preventing a rotary work lifter, a working table or the like from being destructed by pinching a workpiece between the rotary work lifter and the working table or the like and a working machine having the rotary work lifter.